This invention relates generally to desiccant bags and filters for use in receiver/dryers or accumulator canisters of automotive air conditioning systems. More specifically, it relates to a desiccant bag provided with a filter section, and method of making same, such that the desiccant bag effectively combines two separate components, a desiccant bag and a filter, into a single article.
Accumulators and receiver dryers in automotive air conditioning systems utilize desiccant to adsorb moisture, or undesirable substances, which can enter the system through fittings, hoses, connections, and the like. One common method of containing desiccant within the system is in a bag made of porous fabric which is retained in a fixed position within an accumulator or receiver/dryer canister. These canisters also commonly contain a U-bend tube, or pipe, with an orifice in the outside bend at the bottom of the canister to provide oil pickup for lubrication of the system. This orifice typically is covered with a filter device, made of plastic, steel, or aluminum, to assure that particles, dirt, or dust is not circulated into the a/c system.
Accordingly, the present invention integrates a desiccant bag and a filter into a single article such that bag is provided with a filter section. This bag and filter combination is positioned at the bottom of the U-bend tube so that the filter section covers the orifice in the outside bend.
One significant advantage of the invention is cost reduction insofar as the need for a separate filter assembly and a separate operation to attach the assembly to the tube is eliminated. Also, the bag can be fitted tightly around the tube thereby eliminating the possibility of any large particles entering the orifice in the U-bend tube.
Accordingly, the invention provides a simple way for combining a desiccant bag and a filter while at the same time reducing the material and assembly costs associated with separate components. Also, the desiccant bag keeps large particles from entering the orifice in the U-bend tube.
The present invention includes a desiccant bag made from a sheet of porous fabric. The bag comprises a filter section having a yoke, or wall portion, disposed about a central axis to define a sleeve. The bag further includes first and second longitudinal end portions having opposing top and bottom layers comprising a length and a width and having opposing sides connecting the layers. The layers further have opposing first and second ends. The second ends of the layers of the first end portion and the second ends of the layers of the second end portion are connected to form sealed ends while the first ends opposingly and integrally join the end portions with the wall portion so that the first ends run parallel with the central axis and the end portions extend outwardly therefrom.
Additionally, the bag comprises a seam extending across the bag for sealing lengthwise and has first and second seals. The first seal seals together the first ends of the layers of the first end portion across the width thereof adjacent the wall portion and the second seal seals together the first ends of the layers of the second end portion across the width thereof adjacent the wall portion so that the end portions define first and second compartments wherein the first seal and sealed end of the first end portion define opposing ends of a first compartment, and the second seal and sealed end of the second end portion define opposing ends of a second compartment. The first and second compartments are provided with a plurality of desiccant particles contained therein.
Construction of the bag involves providing a sheet of porous fabric having opposing longitudinal and lateral side edges and connecting the opposing longitudinal side edges, such as by ultrasonic, heat fusion and/or stitching procedures, to form a tube-like structure comprising a width and having opposing top and bottom layers, opposing sides for connecting the layers, and opposing first and second ends having openings. Next, spaced first and second seals are placed intermediate the ends of the tube-like structure. The seals seal across the width of the tube-like structure connecting the top layer with the bottom layer so that the ends define a compartment provided with an opening.
The opposing longitudinal edges of the tube between the first and second seals then are sliced lengthwise using a cutting tool or die to form the filter section having a wall portion, or yoke, disposed about a central axis and having first and second openings to define a sleeve. Lastly, the compartments are filled with desiccant and the openings sealed shut so that the ends form sealed ends for containing particles within the compartments.
Accordingly, the filter section receives the end of a U tube through its sleeve and the bag is easily slid thereon until the filter section is situated over an orifice in the bight of a U-bend tube. The bag fits around the U tube so that the filter section can act as a filtering device at the orifice while gravity firmly holds the bag in the canister thereby acting as a method to hold the bag in place. The yoke can be adjusted to fit tightly over the U-bend tube once assembled.
In an alternate embodiment, the desiccant bag comprises only one compartment for containing desiccant particles therein. In this embodiment, a first seal is placed between the ends of the tube-like structure substantially adjacent one opening. A second seal seals this opening. Both seals seal across the width of the tube-like structure and connect the top layer with the bottom layer. The single end portion defines a compartment having an opening. The opposing longitudinal sides of the tube-like structure between the seals are sliced lengthwise using a cutting tool or die to form the filter section. Lastly, the compartment is filled with desiccant and sealed shut so that the end forms a sealed end for containing desiccant particles within the compartment.
Notably, one can integrate different filter material into the wall portion of the bag thereby allowing for different filter characteristics as required by the manufacturer of the accumulator or receiver/dryer canister. As such, if the porous bag material is thought to be too dense to allow for proper lubricant pickup, then a more course filter material may be used in the wall portion at the location where the bag will position over the orifice.
Yet, a further embodiment of the invention involves providing an aperture in the filter section between the first and second openings of the sleeve so that the aperture can be positioned around a separate filter which may already be assembled on the tube. As such, the bag will still be located in place but will not act as a filter.
Therefore, it may be appreciated that an object of the present invention is to provide a single or dual desiccant bag having a filter integrated therein for reducing the material and assembly costs associated with separate components.
It is a further object of present invention to provide both a dual and single compartment desiccant bag having an aperture adapted for receiving a filter on a U-bend tube.
Lastly, it is another object of the invention to provide a desiccant bag with filter integrated therein that fits snugly around the bight in a U-bend tube and keeps large particles from entering the orifice.
Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings.